Aquarium



FIG. 1 is a perspective view of an aquarium showing my new design;

FIG. 2 is an elevational view of one side thereof, the other sides not shown being substantially identical thereto;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for an aquarium, as shown and described. 